Measuring apparatus



1941- R. C. LAWRENCE 2,229,748

MEASURING APPARATUS Filed April 13, 1939 l/Wi/VTO/P RGLAWRl-WCE' Patented Jan. 28, 1941 UNITED. STATES PATENT orncg 2,222,748 MEASURING'APPARATUS Roger 0. Lawrence, Ridgewood, N. J., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application April 13, 1939, Serial No. 267,550

Claims.

and more particularly to an apparatus for measuring internal dimensions of hollow articles.

Objects of the invention are to provide a sim- 5 pie, inexpensive and durable measuring apparatus by'means of which dimensions of articles may be measured expeditiously and with a high degree of accuracy.

In accordance with the above objects, one embodiment of the invention contemplates the provision of an apparatus for measuring internal dimensions of hollow articles, in which a movable measuring bar is suspended intermediate its ends upon two reeds o'r fiat springs attached to oppo- 5 sitesides of the bar with their fiat surfaces perpendicular to the longitudinal axis of the bar. A third reed or fiat spring is attached to the bar with its flat surfaces in the plane of the longitudinal axis of the bar to prevent endwise 20 movement of the bar. The construction and arrangement of the parts are such that the reeds are subjected to torsional bending upon move ment of one end of the bar into engagement with an article being measured.

25 A more complete understanding of the invention may be had from the following detailed description when read in conjunction with the accompanying drawing, in which Fig. 1 is a vertical sectional view of a measur- 30 ing apparatus'embodying the features of the invention;

Fig. 2 is a plan view thereof, with a portion of the enclosing structure broken away to show the supporting reeds for the measuring arm;

35 Fig. 3 is an enlarged fragmentary end elevational view of the apparatus looking from the right in Fig. 1, and

Fig. 4 is an enlarged fragmentary sectional.

view taken on line 44 of Fig. 1.

4 Referring now to the drawing, the apparatus illustrated therein comprises a supporting member having a channel-like cavity ll over which a cover plate I2 is removably attached. A cylindrical arbor i3 has an end flange It by 45 means of which it is attached to one end of the supporting member.- The arbor is provided with a longitudinal bore I5 of rectangular cross-section, which communicates with an enlarged end portion l6 of cavity ll through a slot I! in an 50 end wall l8 of the cavity.

A movable measm'ing bar is mounted within the cavity II and has a reduced end portion 2| which projects through the slot n and into the bore of arbor l3, as best shown in Fig. 1. At-

55 tached at one end to opposite sides of the measat its opposite end to wall 24. The spring is This invention relates to measuring apparatus,

uring bar and intermediate the ends thereof are a pair of reeds or flat springs 2i and 22 (Figs. 2 and 4) the opposite ends of which are secured to opposite side walls 23 and 24, respectively, of the enlarged cavity portion 16. Thesprings 2| and 22 are mounted so that their flat surfaces are normally disposed in a plane perpendicular to the longitudinal axis of the measuring bar. An additional reed or fiat spring 25 is secured at one end to the measuring bar and is attached 10 disposed with its fiat surfaces perpendicular to the springs 2i and 22 and in the plane of the longitudinal axis of the measuring bar, whereby endwise movement of the bar is prevented. It 15 will be understood that the measuring bar is, in effect, pivotally supported intermediate its ends bymeans of the springs, which are subjected, to a slight torsional bending or twisting action upon pivotal movement of the bar. The side wall portions 23 and 24, to which the springs are attached, may be relatively thin, as shown, so that they can be d'eflected inwardly by the increased tension on the springs due to the slight shortening thereof which might result from the 25 torsional bending.

The arbor i3 is provided externally with two fixed hardened steel rails or shoes 28', 28 which extend longitudinally of the arbor and are spaced from each other, as shown in Fig. 3. Diamet rically opposite a point midway between the two fixed rails, the arbor is provided with a radially extending aperture 29. A stud 30 is attached to the reduced end portion of the measuring bar and is adapted to project through the aperture 29 to engage a surface of an article to be measured. A stud 32 is provided on the oppo site end of the measuring bar on the side oppo-' site the article engaging stud, and the cover plate is provided with an aperture 33 through which the stud 32 is adapted to project to engage and operate a movable contacting plunger 35 of any suitable gauging apparatus (none shown), by means of which the movement of the measuring bar may be suitably magnified and visually indicated.

The studs 30 and 32 are spaced equal distances from the bar supporting springs so that the extent of movement of the stud 32 will always be' the same as the extent of movement of the article engaging stud 30. The latter stud is yieldably urged radially outwardly of the arbor by a spring pressed plunger 31 which normally urges the measuring bar in a clockwise direction 55 against an adjustable stop screw 38 mounted in the cover plate l2. I

when employing the apparatus for measuring the internal diameter of a cylindrical article, such as indicated by the broken lines 40 in the drawing, the article is placed on the arbor ll so that the fixed contact rails 28 engage the inner cylindrical surface of the article and thereby properly position it with respect to the movable contact stud 30. If the internal diameter of the article is within predetermined limits, the movable contact stud is moved radially inwardly to an extent corresponding to the diameter of the'article. A corresponding counterclockwise movement is thus imparted to the measuring bar 20, which transmits the movement of contact stud 30 to the stud 32 at the opposite end of the measuring bar.

- As mentioned above, any suitable apparatus (none shown) may be employed for suitably magnifying the movement of the measuring bar and for visually indicating the extent of such movement and thereby the difference between the measured dimension and a predetermined standard.

It will be obvious that by employing fiat springs instead of the usual pivot screws for pivotally supporting the measuring bar, inaccuracies, such as result because of wear of the parts when pivot screws are employed, are eliminated. Also, by arranging the supporting springs as contemplated by this invention, it is possible to obtain a pivotal movement of the measuring bar which approximates that obtained by the use of pivot screws.

It should be understood that the invention is not limited to the particular embodiment thereof herein illustrated and described, except insofar as is defined by the appended claims.

What is claimed is:

1. In a measuring apparatus, a fixed supporting member, a movable member, a flat spring attached at one end to the supporting member and at its opposite end to the movable member, said spring being disposed with respect to said members so that it is subjected to a torsional bending action upon movement of said movable member, and a second fiat spring secured to said members with its fiat surfaces substantially parallel to the longitudinal axis of said movable member.

2. In a measuring apparatus, a movable measuring member, and means-for movably supporting said member, comprising a fixed support, a flat spring attached at one end to the ,measuring member and projecting laterally therefrom and attached at its opposite end to said support, said 5 spring being disposed with its flat surfaces substantially perpendicular to the longitudinal axis of said measuring member, and means for preventing endwise movement of said measuring member, said means comprising a second fiat 10 spring attached to the support and the measuring member adjacent the first spring and disposed with its flat surfaces substantially parallel to the longitudinal axis of the measuring member.

3. In a measuring apparatus, a fixed supporting member, a movable measuring member, and a pair of fiat springs interconnecting said members, said springs being disposed with their fiat surfaces perpendicular to each other and with the fiat surfaces of one of the springs substan- 20 tially perpendicular-to the longitudinal axis of the measuring member.

4. In a measuring apparatus, a movable measuring bar, and means for .supporting said bar comprising a fixed support,'a pair of'flat springs 5 attached at one end to opposite sides of the measuring bar intermediate the ends thereof and projecting laterally therefrom with their fiat surfaces perpendicular to the longitudinal axis of said bar, said springs being attached at their op- 30 posite ends to said support, and a third fiat spring attached at one end to the measuring bar adjacent one of said pair of springs, the said. third spring projecting laterally from said bar, being attached at its opposite end to the support and 35 being disposed with its flat surfaces substantially parallel to the longitudinal axis of said bar. 7

5. In a measuring apparatus, a movable measuring bar, and means-for pivotally supporting said bar, comprising a support, a flat spring ato tached to the bar and having a portion projecting laterally therefrom and attached to a portion of the support, said attaching portion of the support being yieldable to compensate for the shortening of the spring resulting from the torsional bending thereof upon pivotal movement of said measuring bar.

ROGER C. LAWRENCE. 

